Expandable liner for oversized base casing

ABSTRACT

An expandable tubular member comprises a first portion having a first inner diameter and a first wall thickness. A second portion of the expandable tubular member has an increased inner diameter and an increased wall thickness. A transition portion of the expandable tubular member is defined by a wall thickness that varies non-linearly between the first wall thickness and the increased wall thickness.

CROSS-REFERENCE TO RELATED APPLICATIONS

None

BACKGROUND

This disclosure relates generally to methods and apparatus for expanding a tubular member in a wellbore. More specifically, this disclosure relates to methods and apparatus for expanding a tubular member into an oversized base casing.

Expandable casings, liners, and other tubulars are utilized in the construction of wells to line the wellbore. Expandable tubulars are disposed in a well in an unexpanded state and then can be radially expanded to increase the diameter of the tubular. The expansion typically takes place via the application of mechanical expansion tools, hydraulic pressure, or a combination thereof to plastically deform the tubular. Expandable tubulars can therefore provide an increased tubular diameter as compared to the use of conventional tubulars.

Expandable tubulars are often secured in a wellbore by compressing an elastomer between a portion of the expanded tubular and the existing base casing. In certain applications, the existing base casing may have an inner diameter that makes the compression of the elastomer difficult due to the size of the inner diameter of the base casing and the expanded diameter of the expandable tubular. If the inner diameter of the base casing is too large, the expansion of the expandable tubular may not provide sufficient compression of the elastomer or require the use of an increased thickness of elastomer. In the most extreme of these applications, the size of the base casing may prevent the use of conventional expandable tubulars or may require special preparation of the wellbore to accommodate a larger expandable tubular.

Thus, there is a continuing need in the art for methods and apparatus for expanding a tubular member into an oversized base casing that overcome these and other limitations of the prior art.

BRIEF SUMMARY OF THE DISCLOSURE

An expandable tubular member comprises a first portion having a first inner diameter and a first wall thickness. A second portion of the expandable tubular member has an increased inner diameter and an increased wall thickness. A transition portion of the expandable tubular member is defined by a wall thickness that varies non-linearly between the first wall thickness and the increased wall thickness.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the embodiments of the present disclosure, reference will now be made to the accompanying drawings, wherein:

FIG. 1 is a partial sectional schematic illustration of a wellbore with an expandable liner.

FIG. 2 is a partial sectional schematic illustration of a wellbore with an expandable liner having an increased wall thickness in an upper portion of the liner.

FIG. 3 is a partial sectional view of a portion of an expandable liner having an increased wall thickness.

FIG. 4 is a graphical representation of the expansion force required to expand the liner shown in FIG. 3.

FIG. 5 is a partial sectional view of a portion of an expandable liner with the wall thickness transitioning to an increased wall thickness.

FIG. 6 is a partial sectional view of a portion of an expandable liner with the wall thickness transitioning to an increased wall thickness.

FIG. 7 is a partial sectional view of a portion of an expandable liner with the wall thickness transitioning to an increased wall thickness.

FIG. 8 is a graphical representation of the expansion force required to expand the liners shown in FIGS. 5-7.

DETAILED DESCRIPTION

It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.

Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Additionally, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein.

Referring initially to FIG. 1, an expandable tubular member 10 is disposed within a wellbore 12. An upper end 14 of the expandable tubular member 10 is in an overlapping relationship with an existing base casing 16. An expansion cone 18 is moved longitudinally through the expandable tubular member 10 so as to increase the inner diameter of the tubular from an unexpanded diameter 20 to an expanded diameter 22. Anchor members 24 are disposed about the upper end 14 of the expandable tubular member 10 and engage the base casing 16 as the tubular member 10 is expanded. To properly engage the base casing 16 and secure the tubular member 10 to the base casing 16, the anchor members 24 are compressed in the annulus between the tubular and the base casing.

In certain applications, the expanded diameter 22 of the tubular member 10 plus the thickness 26 of the tubular may not provide for sufficient compression of the anchor members 24 in the annulus between the tubular and the base casing 16. In certain embodiments, the thickness of the anchor members 24 may be increased so that sufficient compression can be achieved. In other embodiments, the thickness 26 of a portion of the expandable tubular member 10 can be increased, as shown in FIG. 2. Increasing the thickness 26 in the section of the expandable tubular member 10 onto which the anchor members 24 are mounted allows for the anchor members to be sufficiently compressed in a larger sized base casing 10.

FIG. 3 illustrates a portion of an expandable tubular member 10 having a section 14 with an increased wall thickness 26 and a constant inner diameter 20. The expansion force required to move cone 18 through tubular member 10 is graphically illustrated in FIG. 4 where the horizontal axis is the force in pounds and the vertical axis is distance traveled by the cone. In the example illustrated in FIG. 4, the tubular member 10 has a nominal wall thickness of 0.495 inches and an increased wall thickness 26 of 1.06 inches and is being radially expanded by 8.26 percent.

As can be seen in FIG. 4, the expansion force needed to expand the portion of the tubular member 10 having an increased wall thickness 26 is substantially greater than the expansion force needed to expand the other portions of the tubular member. In certain embodiments, this increased expansion force may exceed the operational parameters of the expansion system and/or the expandable tubular. Therefore, the increased wall thickness 26 is limited by the allowable expansion forces and may not provide the necessary thickness to sufficiently compress the anchor members 24.

In order to reduce the expansion forces required in the portion of an expandable tubular member 10 having an increased wall thickness 26, the wall thickness can be decreased by increasing the inner diameter through the thickened section. Increasing the unexpanded inner diameter reduces the amount of radial expansion that is seen by the increased thickness section. Because the amount radial expansion is decreased, the expansion force is also decreased.

FIGS. 5-7 illustrate alternate embodiments for transitioning the wall of an expandable tubular between a nominal wall thickness and an increased wall thickness. Each of the embodiments shown illustrate one end of the increased wall thickness portion and it is understood that the features shown can be also be present at the other end of the increased wall thickness portion. For the purposes of this disclosure, each end of the increased wall thickness portion is described as having identical features but in certain embodiments, it may be found that having different features on each end of the increased wall thickness portion may be desired. In the description that follows, like numbers are used to refer to like structural features.

Referring now to FIG. 5, expandable tubular member 30 has a nominal inner diameter 32, nominal wall thickness 34, increased inner diameter 36, and an increased wall thickness 38. The outer surface of the expandable tubular 30 has an outer taper 40 along the transition portion between the nominal wall thickness 34 and the increased wall thickness 38. The inner surface of the expandable tubular 30 has an inner taper 42 along the transition portion between the nominal wall thickness 34 and the increased wall thickness 38. The inner taper 42 and outer taper 40 are selected so that the thickness of the wall increases linearly between the nominal wall thickness 34 and the increased wall thickness 38.

Referring now to FIG. 6, expandable tubular 44 has a nominal inner diameter 32, nominal wall thickness 34, increased inner diameter 36, and an increased wall thickness 38. The outer surface of the expandable tubular 44 has an outer taper 40. The inner surface of the expandable tubular 44 is defined by a first fillet radius 46 and a second fillet radius 48 that create a smooth transition along the inner surface. This smooth transition creates a wall thickness that varies nonlinearly in the transition portion between the nominal wall thickness 34 and the increased wall thickness 38. In certain embodiments, the outer surface of the expandable tubular 44 may also have one or more fillet radii along the transition portion between the nominal wall thickness 34 and the increased wall thickness 38.

Referring now to FIG. 7, expandable tubular 50 has a nominal inner diameter 32, nominal wall thickness 34, increased inner diameter 36, and an increased wall thickness 38. The outer surface of the expandable tubular 50 has an outer taper 40 along the transition portion between the nominal wall thickness 34 and the increased wall thickness 38. The inner surface of the expandable tubular 50 has an inner taper 52 along the transition portion between the nominal wall thickness 34 and the increased wall thickness 38. The inner taper 52 and outer taper 40 are substantially equal so that the wall thickness remains constant until the inner taper 52 intersects with the increased inner diameter 36.

FIG. 8 illustrates the results of an analysis performed on expandable tubulars having features such as those shown in FIG. 5-7. In the analysis illustrated in FIG. 8, finite element analysis was used to simulate the expansion of a tubular member with an expansion cone having an outer diameter of 16.250 inches. For the purposes of this analysis, the nominal inner diameter, nominal wall thickness, increased inner diameter, increased wall thickness, and the outer taper were identical for each analyzed embodiment. The chart below lists the common dimensions of the expandable tubular used in the illustrated analysis.

Nominal Inner Diameter (32) 15.010 inches Nominal Thickness (34)  0.495 inches Increased Inner Diameter (36) 15.800 inches Increased Thickness (38)  0.970 inches Outer Taper (40)    5 degrees

The inner taper 42 for the linearly increasing wall thickness embodiment of FIG. 5 was 2.27 degrees. For the non-linearly increasing wall thickness embodiment of FIG. 6, the first fillet radius 46 was 25.4 inches and the second fillet radius 48 was 100 inches. For the constant wall thickness embodiment of FIG. 7, the inner taper 52 was 5 degrees.

Referring back to FIG. 8, expansion force curve 54 represents the expansion force curve for the expansion of the embodiment of FIG. 5. Expansion force curve 56 represents the expansion force curve for the expansion of the embodiment of FIG. 6. Expansion force curve 58 represents the expansion force curve for the expansion of the embodiment of FIG. 7.

Each of the expansion force curves 54, 56, 58 is substantially equal during the expansion of the portions of the tubular where the inner diameter and thickness are constant. The expansion force curves 54, 56, 58 diverge as the diameter and/or thickness of the tubular transitions from the nominal thickness portions to the increased thickness portions. Expansion force curve 54 shows an increase in expansion force during the transition portion between the nominal thickness portions and the increased thickness portion of the tubular. This increased expansion force is due to the increasing wall thickness of the tubular and the changing expansion percentage of the tubular. Because the wall thickness is increasing linearly and the expansion percentage is decreasing non-linearly, the expansion force is changing in a non-linear fashion. It is also observed that the transitions from the nominal thickness sections to the increased thickness section require more expansion force than expanding through either of the constant diameter/constant thickness sections.

The expansion force curve 56 shows that by increasing the wall thickness in a non-linear manner (as shown in FIG. 6), the increased forces seen in expansion force curve 54 can be reduced. The expansion force curve 56 shows little increase in the expansion force over the transition portions as compared to the constant wall thickness sections.

The expansion force needed to expand the expandable tubular shown in FIG. 7 is represented by expansion force curve 58. Surprisingly, the expansion force curve 58 indicates that the expansion force through the transition between wall thicknesses actually decreases relative to the expansion force needed for the constant wall thickness portions. When expanding a tubular having the features shown in FIG. 7, the maximum expansion force is shown to occur in the section with an increased wall thickness.

Thus, using any of the embodiments illustrated in FIGS. 5-7 can allow the expansion of a tubular having a portion with an increased wall thickness while maintaining expansion forces within desired ranges. The embodiments disclosed herein may be used in applications where a portion of an expandable tubular may require an increased outer diameter after expansion. For example, embodiments incorporating one or more of the concepts disclosed herein may be used to create an increased outer diameter portion for use as a hanger joint and/or to achieve a seal with an existing casing or the wellbore. These embodiments may be especially useful in applications where the maximum diameter of the unexpanded system is limited by a wellbore restriction.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure. 

What is claimed is:
 1. An expandable tubular member comprising: a first portion having a first inner diameter and a first wall thickness; a second portion having an increased inner diameter and an increased wall thickness; and a transition portion defined by a wall thickness that varies non-linearly between the first wall thickness and the increased wall thickness.
 2. The expandable tubular member of claim 1, wherein the transition portion includes a first length over which the wall thickness remains constant and the inner diameter increases and a second length over which the wall thickness increases and the inner diameter remains constant.
 3. The expandable tubular member of claim 2, wherein the wall thickness in the first length of the transition portion is substantially equal to the first wall thickness.
 4. The expandable tubular member of claim 2, wherein the inner diameter of the second length of the transition portion is substantially equal to the inner diameter of the increased wall thickness portion.
 5. The expandable tubular member of claim 1, wherein the transition portion has either an inner surface or an outer surface defined by at least one radius.
 6. The expandable tubular member of claim 1, wherein the transition portion has an outer surface at least partially defined by an outer taper.
 7. The expandable tubular member of claim 6, wherein the transition portion has an inner surface at least partially defined by an inner taper that is substantially equal to the outer taper.
 8. The expandable tubular member of claim 6, wherein the transition portion has an inner surface having a length that is substantially parallel to the outer surface.
 9. An expandable tubular member comprising: a first portion having a first inner diameter and a first wall thickness; a second portion having an increased inner diameter and an increased wall thickness; and a transition portion having a first end coupled to the first portion and a second end coupled to the second portion, wherein the transition portion has a wall thickness that increases in a non-linear fashion from the first wall thickness at the first end to the second wall thickness at the second end.
 10. The expandable tubular member of claim 9, wherein the transition portion includes a first length over which the wall thickness remains constant and the inner diameter increases and a second length over which the wall thickness increases and the inner diameter remains constant.
 11. The expandable tubular member of claim 10, wherein the wall thickness in the first length of the transition portion is substantially equal to the first wall thickness.
 12. The expandable tubular member of claim 10, wherein the inner diameter of the second length of the transition portion is substantially equal to the inner diameter of the increased wall thickness portion.
 13. The expandable tubular member of claim 9, wherein the transition portion has either an inner surface or an outer surface defined by at least one radius.
 14. The expandable tubular member of claim 9, wherein the transition portion has an outer surface at least partially defined by an outer taper.
 15. The expandable tubular member of claim 14, wherein the transition portion has an inner surface at least partially defined by an inner taper that is substantially equal to the outer taper.
 16. The expandable tubular member of claim 14, wherein the transition portion has an inner surface having a length that is substantially parallel to the outer surface.
 17. A method for expanding a tubular member comprising: disposing a tubular member in a wellbore, wherein the tubular member includes a first portion having a first inner diameter and a first wall thickness, a second portion having an increased inner diameter and an increased wall thickness, and a transition portion defined by a wall thickness that varies non-linearly between the first wall thickness and the increased wall thickness; displacing an expansion cone longitudinally through the tubular member to generate an expansion force that radially expands the tubular member, wherein the expansion force needed to radially expand the transition portion is less than the expansion force needed to radially expand the first portion.
 18. The method of claim 17, wherein the transition portion includes a first length over which the wall thickness remains constant and the inner diameter increases and a second length over which the wall thickness increases and the inner diameter remains constant.
 19. The method of claim 17, wherein the transition portion has an outer surface at least partially defined by an outer taper.
 20. The method of claim 19, wherein the transition portion has an inner surface at least partially defined by an inner taper that is substantially equal to the outer taper. 